• 오토저널
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• 제6권4호
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• pp.36-45
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• 1984

The relationship between vehicle driving pattern and fuel consumption in urban area was studied in Seoul along three representative routes using a test car equipped with all the instruments required for recording modes of traffic and measuring fuel consumption. Correlation with idle speed, fuel consumption and CO concentration of car in use was also measured. The average vehicle speed in Seoul was 31.4 km/h and the time spent in different modes was 23.0% in idle mode, 22.5% in acceleration mode, 32.4% in cruising mode and 22.3% in deceleration mode, respectively. Hence, traffic flow was suggested to be relatively smooth. Fuel consumption per unit distance, .phi. was closely related with trip time spent per unit distance, t, and correlation coefficient obtained from the test car was 0.925, and the relationship between .phi. and t was also obtained from the linear regression with the following equation. .phi.=42.87+0.38 t. Idle speed of vehicle in use was mostly adjusted low and cars which were over the permissible standard of CO concentration (4.5%) were 50% or more. As the idle speed decreased, the fuel consumption was decreased, while the CO concentration was increased. Therefore, the decrease of fuel consumption can not be expected with only a decrease in idle speed.

• Bulletin of the Korean Chemical Society
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• 제31권6호
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• pp.1543-1550
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• 2010

This work presents oxidation of formic acid on Bi-modified Pt nanoparticles of various sizes. The sizes of the studied Pt nanoparticles range from 1.5 to 5.6 nm (detailed in Rhee, C. K.; Kim, B.-J.; Ham, C.; Kim, Y.-J.; Song, K.; Kwon, K. Langmuir 2009, 25, 7140-7147), and the surfaces of the Pt nanoparticles are modified with irreversibly adsorbed Bi. The investigated coverages of Bi on the Pt nanoparticles are 0.12 and 0.25 as determined by coulometry of the oxidation of adsorbed hydrogen and Bi, and X-ray photoelectron spectroscopy. The cyclic voltammetric behavior of formic acid oxidation reveals that the adsorbed Bi enhances the catalytic activity of Pt nanoparticles by impeding a poison-forming dehydration path with a concomitant promotion of a dehydrogenation path. The chronoamperometric results indicate that elemental Bi and partially oxidized Bi are responsible for the catalytic enhancement, when the Bi coverages on Pt nanoparticles are 0.12 and 0.25, respectively. The size effect of Bi-modified Pt nanoparticles in formic acid oxidation is discussed in terms of specific activity (current per unit surface area) and mass activity (current per unit mass).

• 한국염색가공학회지
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• 제11권6호
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• pp.51-58
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• 1999

The dimensional properties on polyester warp knitted fabrics with various lengths of underlap were studied. The results indicated that loop density increased with decreasing loop length and loop density of satin warp knitted fabric are a little higher than that of reverse satin warp knitted fabrics at a constant loop length. As the distance of underlap becomes shorter, the weight per unit area and thickness increases, the bulkiness decreases and the shrinkage of knitted fabrics become larger toward wale in satin warp knitted fabric and toward the course in reverse satin warp knitted fabric.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.945-949
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• 2002

This part of specifies the method for determining the dynamic stiffness of resilient materials used under floating floors. Dynamic stiffness is one of the parameters that determine the sound insulation of such floors in dwellings. This part applies to the determination of dynamic stiffness per unit area of resilient materials with smooth surfaces used in a continuous layer under floating floors in dwellings

• 한국토양비료학회지
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• 제9권3호
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• pp.117-132
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• 1976

Fertilizer has been played greately on the agricultural development as well as food production and agriculture has also promoted the development of fertilizer industry. There were, however, many difficulties between supply and demand of fertilizer throughout the decade. In this regard, this paper is involved with present situation and prospect of commercial fertilizers, in view of domestic and international scheme on resources, production, and demand within the limited information. Brief history of commercial fertilizer in Korea has outlined for the introduction and fertilizer consumption per unit area also discussed.

• JSTS:Journal of Semiconductor Technology and Science
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• 제1권3호
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• pp.189-192
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• 2001

A simple metal-insulator-metal (MIM) capacitor in a standard $0.25{\;}\mu\textrm{m}$ digital CMOS process is described. Using all six interconnect layers, this capacitor exploits both the lateral and vertical electrical fields to increase the capacitance density (capacitance per unit area). Compared to a conventional parallel plate capacitor in the four upper metal layers, this capacitor achieves lower parasitic substrate capacitance, and improves the capacitance density by a factor of 4. Measurements and an extracted model for the capacitor are also presented. Calculations, model and measurements agree very well.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 춘계학술대회논문집
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• pp.65-68
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• 1997

Vickers hardness is defined as indenting force per unit area indented by a pyramid-shaped diamond at the hardness test. It is well known that Vickers hardness has a direct relation with the flow stress of the strain-hardened material. This relation was theoretically investigated and the result was summerized in a form of algebraic equation in the last paper. In the present paper and experimental validation of this theoretical relation is given along with mathematical formulas for conversion of Vickers hardness into the flow stress in the strain-hardened material for practical use.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 춘계학술대회논문집
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• pp.69-72
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• 1997

The indentation process in the Vickers hardness test is a kind of controlled local plastic deformation. Vickers hardness is defined as indenting force per unit area indented by a pyramid-shaped diamond at the hardness test. That is a measure of mechanical resistance against indentation of a rigid body into the deformable material. Therefore it is well known that Vickers hardness has a direct relation with the flow stress of the strain-hardened tmaterial. This relation is theoretically investigated and the result is given for use in practice.

• 한국막학회:학술대회논문집
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• 한국막학회 2004년도 춘계 총회 및 학술발표회
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• pp.144-146
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• 2004

Various polymeric hollow fiber membranes have been prepared and been used widely due to their high surface area per unit volume and high permselectivity. However, the organic materials are only limited to mild operating conditions because of their weak thermal stability and ease of fouling.(omitted)

• 한국광학회:학술대회논문집
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• 한국광학회 2008년도 동계학술발표회 논문집
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• pp.355-356
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• 2008

The light extraction efficiencies of GaN-based light-emitting diodes (LEDs) grown on differently patterned sapphire substrates were investigated by using the ray tracing method. It was found that angle of the pattern surface against the sapphire surface, the number of pattern per unit area were important structural factors for high extraction efficiency.